Telephone earpiece or receiver



Dec. 1,1925. 1,563,888

. C. E. WILLIAMS TELEPHONE EARPIECE OR RECEIVER Filed March 5. 1923 iii)Patented Dec. 1, 1925.

K F FICE.

CHARLES'E. WILLIAMS, :OF CHICAGO, ILLINOIS.

TELEPHONE EARPIECE"OR RECEIVER.

Application filed March 5, 1923.

To all whom it-mag concern:

Beit known that 1, Ciiannss E. WiLLLmis, a citizen of the United States,residing at Chicago, inthecounty'iof Cook and State of Illinois,haveinvented a new and useful Improvement in Telephone Earpieces orReceivers, of which the following 'is aspecific'ation.

My present invention relates' to improvements in'telephoneear-pieces orreceivers, and "has special reference to=the-variety of telephoneear-pieces or-receivers which are employed in microphoneappa 'atus forthe use of persons whose hearing is impaired. Persons with impaired"hearing can usually hear different characters of sound with differentdegrees of readiness, and different transmitters have been provided,each of which is capable of amplifying and trans mitting with greateremphasis different character of sound. Also apparatus is made in which anumber of different transmitters have been combined in a single circuitwith a single ear-piece, or pair of earpieces, so that by selectingsuitable transmitters the sound which the person hears will be renderedmore normal, readily un derstood and pleasing. A number of suchtransmitters have been produced which are extremely sensitive anddesirable, but it is found that not more than six of such transmitterscan advantageously be inserted in a circuit carrying approximately threevolts of current and that if a current with a greater voltage isemployed the carbon granules in the transmitter pass a fluctuatingcurrent which causes a sound in the ear-piece or receiver, generallydescribed as frothing, which materially interferes with the transmissionof the desired sounds.

The object of my present invention is the provision of an ear-pieceorreceiver of the microphone type with which an increased number oftransmitters may be connected. I prefer to carry out my invention bymeans of the instrumentalities illustrated in the accompanying drawings,in which Fig. l is a central section of a conven tional form ofmicrophone ear-piece or receiver in which my invention is embodied.

Fig. 2 is a view of the structure shown in Fig. 1 looking toward the capor closure but with the cap or closure and diaphragm removed, and

Fig. 3 is a diagrammatic view of the cir- Serial NO. 622,882.

cuits involved in the operation of my inven tion.

Similar reference characters irefer to similar p artsthroughout theseveral views.

The usual microphone earpiece or receiver con'iprises a casing 10,preferably formed in whole or in :part of an insulating material, suchas hard rubber. The casing is usually of cylindrical formand open at oneend. Around the open end, thecasing is exteriorlythreaded 'to receivethe \interiorl'y threaded flange of a centrally apertured cap ll. Theflange of the cap is thickened somewhat at its *base sto provide aninteriorannular shoulder .12, which comes opposite the edge of casing10, and between the edge of the casing and shoulder is secured adiaphragm 13.

Secured to the interior face of the bottom of the casing by any suitablemeans, such as the machine screws 14, is a plate 15 to dia metricallyopposite portions of which are secured, as by machine screws 16,brackets 17 of magnetically permeable material. These brackets may bedescribed as of J-shape, the hooked ends 17 being secured to plate 16,and the stem portions 17 ex tending toward and alining with each other.The ends of the stem. portions opposite to the hooks have lateralprojections 17 which extend in parallel relation toward and close lyadjacent to diaphragm 13. r

In the usual form of microphone ear-piece or receiver each stem portion1'7 is provided with a single coil 18 and, 18 of magnet wireelectrically connected in series and included in the circuit coming fromthe transmitter. But, as heretofore alluded to, the present transmitterscannot operate to advantage in a circuit having an electro motive forcein excess of three volts, and no more than six suchtransmitters can beadvantageously operated in such a circuit. I have, therefore, providedeach stem portion 1'7 of brackets 17 with an additional coil 19" and 19which are themselves electricallyconnected in series, but which have noelectrical connection with the other two coils. When the circuit ofwhich coils 19 and 19 form a portion are energized with a current ofsubstantially three volts, or such as can be produced with twocommercial dry cells, any number of transmitters less than seven may beinterposed in the circuit, and the action of' these additionaltransmitters upon the diaphragm will be combined with the action of thetransmitters in the circuit of which coils 18 and 18 form a portion. InFig. 3, I have indicated the circuits involved in the practice of myinvention. In Fig. 3 18 and 18 indicate one pair of coils, and 19 and 19the other pair of coils. The coils 18 and 18 are connected in series inthe circuit comprising conductor C and battery D, and transmitters E,While coils 19 and 19 are connected in series in circuit comprisingconductors C battery D and transmitters E In this manner the possibilityof adapting an instrument to the needs of a particularpatient areincreased without disadvantageously effecting the action of therespective elements of which the instrument is composed.

IVhat I claim is:

1. In an instrument for assisting the partially deaf including aplurality of independent electric circuits, each of which includes aplurality of microphones in series, a telephone ear-piece or receiverincluding an electro-magnet having independent coils included in therespective afore-mentioned circuits.

2. In an instrument for assisting the partially deaf, including twoindependent electric circuits each of which includes a plurality ofmicrophones in series, a telephone earpiece or receiver including anelectro-magnet having two independent pairs of coils, each pair of coilsbeing included in one of the aforementioned circuits.

3. A telephone ear-piece or receiver comprising a casing, an aperturedclosure therefor, a diaphragm secured to said casing by said closure andopposite the aperture thereof, elements of magnetically permeablematerial mounted in said casing and extended adjacent to said diaphragm,independent coils of conductor encircling said elements, and conductorsextending between said coils to form a plurality of independentcircuits, and a plurality of microphones included in series in each ofsaid independent circuits.

Signed at Chicago, county of Cook and State of Illinois, this 27th dayof Feb, 1923.

CHARLES E. WILLIAMS.

